In railroad yards there is a need for convenient, small, and relatively cheap means for moving railway cars (or railcars) short distances without having to hook them up to a locomotive or other separate moving engine car which must push or pull the car to the desired location. This method is cumbersome and hard to use in confined or limited spaces. This need also exists outside of railroad yards where railway cars are used in connection with track construction, maintenance, or other tasks which require the moving of cars short distances and often in opposite directions. For example, a railway car is useful for holding and transporting new railroad ties when the old ties are replaced, and for holding and transporting the old ties when they are removed. In such an application, the railcar must repeatedly be moved short distances to stay near where the ties are being replaced. Obviously, a locomotive or similar device would be unsuitable for such use since it would take up an inordinate amount of space and would be inefficient and expensive. The railcar could be moved by hand, but this is difficult and expensive in terms of manpower required.
Various devices intended for use in conveniently moving railway cars limited distances have been proposed in the prior art. These include powered devices having rollers that are placed under a railway car wheel on the track, the rollers being powered to move the wheel and thus the car; the rollers sometimes are placed only on the periphery of the wheel to move it. Examples of these devices are disclosed in Stewart et al., U.S. Pat. No. 3,828,690, Stewart, U.S. Pat. No. 3,232,240, Stewart, U.S. Pat. No. 3,120,741, and Osthoff, U.S. Pat. No. 1,646,310. Though the disclosed devices are an improvement over moving the cars by locomotive or by hand, they are rather complicated, require a considerable expenditure of energy, and rely on friction between the device and the wheel or track, the lack of which may be a problem.
Other prior art devices include Yard, U.S. Pat. No. 3,653,330, and Kilness, U.S. Pat. No. 2,621,892, which attach to the wheel periphery and track and which are operated by hand. Other references include Roderwald, U.S. Pat. No. 1,911,531, which discloses an apparatus for converting the power of the moving train car axle into electrical power, by use of a dynamo, for lighting the train.
There remains a need for a device which is easy to install and remove, is relatively small and inexpensive, and which does not depend on exact placement between the wheel and the track or on the track for proper operation.